Figure 8.

Effect of all-trans retinoic acid (ATRA) on cytokine-induced SKALP/elafin and hBD-2 gene expression in skin equivalents. Human skin equivalents were stimulated the last 4 days of culture with a mixture of 10 ng/ml of IL-1α, 5 ng/ml of TNF-α, and 5 ng/ml of IL-6 (CM) in the presence or absence of ATRA (10⁻⁶ or 10⁻⁷ mol/L). RNA was isolated, and gene expression of SKALP/elafin (A) and hBD-2 (B) was determined by qPCR. Treatment with ATRA caused a significant decrease of cytokine-induced expression of SKALP/elafin (P < 0.05) and hBD-2 (P < 0.01, analysis of variance, repeated design). hBD-2 expression was significantly affected by both ATRA concentrations (P < 0.02) whereas SKALP/elafin expression was only affected by the highest ATRA concentration (P < 0.05, Duncan’s multiple range test).